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Crash

Discussion in 'Phantom 2 Vision + Discussion' started by Raf, Jan 9, 2015.

  1. Raf

    Raf

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    Hello,
    I have problem with my Phantom 2 Vision Plus. Today I was flying it, I had to shoot the view from a building, still to be build, to present to potential clients.
    The top of the building would be 68 meters. Every time I send it up, the connection got broken between 40 and 50 meters height. Everytime I let it come down (going home) and tried it again.
    I did this 3 times, never worked fine. The last time, all of a sudden the drone started to wobble and started to come down very fast, I had no control anymore. I tried to catch it to break the fall, it flew a bit further and crashed upside down.
    What can be the problem? I don't know if I can fly it again. Imagine it would have ended up in front of a car, in water, hurt somebody...
    The max height was set to 120meters, I had 9 satelites on the GPS, no magnetic sources in the neighbourhood, all batteries were fine. It was connected to an iPhone.
    There was no reason whatsoever for this to happen.
    I hope you guys can help me out.

    Thank you !
     
  2. rotorwash

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    sounds like a VRS
     
  3. eyecon82

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    Do you have prop guards?
     
  4. houstonpilot

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    I would agree, considering the same issue recurred multiple times, and in the same location.
     
  5. dalebb

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    What is a VRS?
     
  6. Raf

    Raf

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    This a clip of the crash :

    https://www.youtube.com/watch?v=OZUMFgFFYwY&feature=youtu.be

    Stupid question : what is a VRS ??

    And yes, I am using prop guards, but I always use them, it was never a problem.
     
  7. houstonpilot

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  8. eyecon82

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    The prop guards are your issue then for sure. They cause VRS
     
  9. Raf

    Raf

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    A Vortex Ring State, thanks for the info, never heard about it...
    Maybe I didn't explain it very clear, but it came down 3 times nice and easy, because the connection broke (going home).
    Only the last time it started wobbling and descend very fast.
    So I don't know if VRS can break the connection and let it come down normal, a few minutes later causing a crash.
     
  10. Fplvert

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    :D
    It sounds like you were loosing the control signal if you had the RTH kick-in. Just a guess, was your antenna pointing at the bird? Were you directly below the bird? If so, you should angle the control antenna so the side faces the bird, or stand further away.
    The crash does sould like VRS, which is when your bird was coming down in it's own prop wash. Obviously, you can't control the bird when its doing the RTH, did you try to regain control by switching S1?
     
  11. dalebb

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    thanks for the info, there are times you want to come down quick and the video showed how to do that and why the phantom comes down so slowly.
     
  12. dalebb

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    i dont think it was a stupid question, i just learned something new.
     
  13. Raf

    Raf

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    Yes, the point of the antenna was towards the drone, and I was directly underneath it.
    I tried switching to S1 and recover control the first times and it worked.
    The last time this did not work, it came down so fast, I couldn't get any control anymore.
     
  14. russianfront

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    Prop guards are now needed to stop minor prop strikes which cause ESC wiring to burn up. But said prop guards also contribute to VRS otherwise known as death spiral.
    Isn't that called a negative feedback loop? DJI must be loving all of these crashes as it seems that 50% of the victims whip out their credit card and buy another one the same day.
     
  15. Meta4

    Meta4 Moderator
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    Straight up is always the trickiest angle for good signal. Pointing the end of the antenna at the Phantom gives the weakest signal. This is why you were losing signal.
    Prop guards cause more problems than they prevent.
    There would have been no crash if this Phantom had no propguards as they make it much easier to get into VRS (and probably harder to get out).
     
  16. moto phantom

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    Usually VRS happens when you are coming down. From your video it appears you are either stationary or ascending. If you have a low battery, you can have current overdraw where the motors spool down - although they keep running they simply aren't running fast enough to give you lift. This will also cause a wobbling descent.
     
  17. MapMaker53

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    When flying high and close, it may be better to actually point the rc antenna parallel to the ground so a wider signal off the length of that antenna reaches the end of the quad's antenna, rather than a situation where both quad and rc antennas are pointing end to end at each other which creates the weakest link. Those more knowledgeable can correct me if I'm wrong. I think the rc antenna is made to pivot so you can optimally adjust it for different situations.
     
  18. msinger

    Approved Vendor

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    MapMaker53, correct. The arrows in the image below should point at your Phantom at all times.
     

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  19. clayton4115

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    can anyone please tell me whether I can use my FC40 prop guards on the vision+ i am intending to buy?
     
  20. fastsmiles

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    Prop guards have a bad reputation for contributing to VRS crashes. :D